Question

Why does this work well:

cout << "foo";

While this doesn’t?

(&cout)->operator<<("foo");

It works fine with numeric values so I guess it’s something related to override. (I’m using the MS Visual C++ compiler.)

Answer 1

operator<< is implemented as a member function for only a limited number of types. For other types, it’s implemented as a global overload like:

std::ostream &operator<<(std::ostream &os, T const &t) { 
    // write the data here
}

The syntax you used will only work with the overloads that are implemented as member functions, not as globals.